It is broadly recognized that human beings have created a broad variety of structures for such as protection from the elements, storage of tools, travel on bodies of water and the like. Typically such human-built structures have a framework and covering elements over the framework. The framework provides shape and strength, and the covering elements close openings between framing elements to provide protection, for example, to persons or items within the structures, and support, for example, roofs, walls and floors.
Human-made structures as defined above include, for example, conventional frame houses, the framework for which is typically a matrix of interconnected beams and boards, and the covering elements for which may take a variety of forms, such as clapboards, bricks or stones, tile (roofs), plywood panels, and the like. Such structures also include, for example, high-rise buildings, which typically have a framework of steel beams and a covering of wall, roof, ceiling and floor elements. Framed structures in the sense meant here also includes those with the capacity to contain forces from within, for example silos, concrete forms and tanks, as well as to resist forces from the outside, which may include not only the elements which land based shelters afford, but also water in the manner of boat or ship hulls. Other kinds of structures include portable units like tents, the framework for which may be inter-connectable rods and bars, and the coverings for which may be fabric units. Such portable units are designed typically such that the coverings, which may broadly be termed skins, may be removed and the frameworks dismantled or even folded up into a smaller package for transport and storage. Framed structures in the admittedly broad sense intended herein further includes those required to support little more than their own weight and stand against the wind, for example towers, antennae, wings, fins, or airfoils. Also included among framed structures are those with the capacity to rotate or roll, for instance, turntables, carousels, turbines, propellers, and (most fundamentally) wheels. Many types of farm, ranching, fishing, warehousing, containerizing, palletizing, road-building, shipping, airborne and mining equipment and machinery utilize framed structures within the meaning of phrase intended here, to give but several examples. Whilst some framed structures provide protection or containment from all directions, others may be intended to bear loads and/or protect against the elements primarily from above or below, for example canopies, decks, scaffolds, piers, docks, quays, rafts, and broadly speaking, platforms of all kinds.
As the human population becomes more numerous and mobile, and as experience has been gained in mass production techniques, it has been recognized that standardization provides cost benefits and expanded use, and it is clear that inventions that increase standardization, lower cost, and expand use for structures for human purposes are clearly needed. It is also clear that portability is important for structures of many sorts, and an improvement in characteristics of portability for structures is almost always desirable.